From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:57579)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <alex.bennee@linaro.org>) id 1ahyKa-0004mD-Vr
	for qemu-devel@nongnu.org; Mon, 21 Mar 2016 07:49:09 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <alex.bennee@linaro.org>) id 1ahyKX-0000wn-PS
	for qemu-devel@nongnu.org; Mon, 21 Mar 2016 07:49:08 -0400
Received: from mail-wm0-x22d.google.com ([2a00:1450:400c:c09::22d]:38249)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <alex.bennee@linaro.org>) id 1ahyKX-0000wg-Gw
	for qemu-devel@nongnu.org; Mon, 21 Mar 2016 07:49:05 -0400
Received: by mail-wm0-x22d.google.com with SMTP id l68so118430415wml.1
	for <qemu-devel@nongnu.org>; Mon, 21 Mar 2016 04:49:05 -0700 (PDT)
References: <56EEF805.8040008@freebsd.org> <56EFB99D.3040109@redhat.com>
	<CAFEAcA-eSQgsqeJb4UC+fKOrETgHMUd87LsQABDfV75yhdeKOw@mail.gmail.com>
	<56EFD9C4.4090601@redhat.com>
From: Alex =?utf-8?Q?Benn=C3=A9e?= <alex.bennee@linaro.org>
In-reply-to: <56EFD9C4.4090601@redhat.com>
Date: Mon, 21 Mar 2016 11:49:02 +0000
Message-ID: <87r3f4rqz5.fsf@linaro.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Subject: Re: [Qemu-devel] [FreeBSD] Host build i386 failing to build aarch64
	targets
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, Sean Bruno <sbruno@freebsd.org>, QEMU Developers <qemu-devel@nongnu.org>


Paolo Bonzini <pbonzini@redhat.com> writes:

> On 21/03/2016 10:35, Peter Maydell wrote:
>> > x86 can actually do 64-bit atomic loads and stores through the FPU, but
>> > I'm not sure about other 32-bit targets?
>>
>> As I say, ppc32 linux is one that can't -- see commit 8a5956ad6392f1155
>> for last time this came up.
>
> Yes, I remember that.  Loads and stores are different from RMW
> operations, though.
>
>> Ideally we should put a compile-time assert in the atomic ops that
>> the data being operated on isn't larger than sizeof(void*) so that
>> this is a compile time error on all 32-bit hosts rather than just
>> a small subset of them.
>
> Yes, I will do it if Alex doesn't beat me to it.

I'm working on it now.

 - fix build failures on 32bit hosts (Linux/BSD)
 - add compile-time assert for sizeof <= sizeof (void*)

Anything else?

>
> Paolo


--
Alex Bennée